Pyroxylin solvent



UNITED STATES ROWLAND B. MITCHELL, 0F ATHOL, MASSACHUSETTS, ASSIGNOR T0ATHOL MANU PATENT OFFlCE.

FACTURING COMPANY, OF ATHOL, MASSACHUSETTS, A CORPORATION OF MASSA-CHUSETTfi.

nannies.

Specification of Letters Patent.

PYBOXYLIN SOLVENT.

No Drawing. Original application filed August 21, 1920, Serial No.405,053. Divided. and. this application filed February 9, 1921. SerialNo. 443,629.

To all whom it may concern:

Be it known that I, ROWLAND B. MITCHELL, a citizen of the United States,residing at Athol, in the county of Worcester and State ofMassachusetts, have invented certain Improvements in Pyroxylin Solvents,of which the following description is a specification.

This invention relates to solvents for pyroxylin and is of particularutility in processes of coatingfabrics with pyroxylin compounds, animportant example of such processes beingthe manufacture of artificialleather.

I have discovered that by using ethyl propionate as the main solvent,and toluol as the diluent, a mixtureis obtained which has great solventpower in view of the small percentage of solvent, the toluol actingalmost or quite as a latent solvent. I have found this combinationhighly satisfactory in practice and produces good artificial leatherwhen used commercially. Care should be taken to remove the water fromall the constituents of the mixtureowing to the well known fact thatWater must not be present in pyroxylin solvents.

Other suitable solvents may be used to replace a part of the ethylpropionate if desired.

The following table gives sucha diluted solution, which I have foundsuccessful and which is at present cheaper, owing to the fact that ethylacetate is now cheaper than ethyl propionate, but I prefer the ethylpropionate mixed with the acetate.

Ethyl propionate 20% Ethyl acetate 10% Toluol 501% Ethyl alcohol 20%"lution:

Ethyl propionate 30% Toluol Ethyl alcohol 20% It will readily beappreciated by those skilled in this art that the exact proportions offthe ingredients will vary with the reguirements of the product, thenature of he process in which it is used, and the conditions under whichthe process is practised. It will also be understood that othersubstances than those particularly mentioned above can be used withethyl propionate and toluol.

For the purpose of coating fabrics a solution of pyroxylin in thissolvent is made,

the percentage of pyroxylin used varying widely with the requirements ofthe product, and a'coating of this solution then is spread on the fabricafter which the solvent is evaporated. The pyroxylin dissolves readilyindeed in this solvent, it spreads smoothly, and dries without wrinklesor bloom if given proper treatment and if all water is eliminated fromthe materials.

A good artificial leather is produced economically with great ease bythe use of this solvent.

This application is a division of co-pending application Serial No.405,053 filed August 21, 1920, and it is limited to the solvent.

in which ethyl acetate is used, the claims common to the two forms ofsolvents above described being presented in the parent application.

What is claimed as new is:

1. A solvent forpyroxylin consisting essentially of ethyl propionate,toluol, ethyl alcohol and ethyl acetate.

2. A solvent for pyroxylin consisting substantially of eth l propionate20%, toluol 50%, ethyl alco 01 20% and ethyl acetate 10%.

In testimony whereofI have signed my name to this specification.

RUWJLAND 1e. lurrcnunt.

Patented Nov. I5, I921.

